Testosterone: Benefits, Risks Unknown

Experts Urge More Research of Testosterone Therapy

From the WebMD Archives

Nov. 12, 2003 -- Thousands of middle-aged men are getting testosterone creams, gels, and patches for flagging strength and libido. But there's little evidence that testosterone therapy works for the normal aging male -- or that it's even safe, an expert panel says.

Their report calls for a careful study of the risks and benefits of testosterone therapy in normal aging men. The committee also calls for more prudent prescribing by doctors.

To review and assess what is known about the safety and efficacy of testosterone therapy in older men, the National Institute on Aging and the National Cancer Institute assembled an expert committee of the Institute of Medicine. After a year of study, the committee has recommended going forward with future trials.

"We were struck by the paucity of placebo-controlled trials to identify benefits and risks," said researcher Dan G. Blazer, MD, a professor of psychiatry and behavioral sciences at Duke University Medical Center.

Blazer and members of his committee held a news teleconference today.

It's a hot-button issue -- whether sexual virility, osteoporosis, strength, and stamina are related to the aging male's inevitably declining testosterone level.

Testosterone therapy has been FDA approved for male hypogonadism, a condition of low testosterone production. But many doctors prescribe it for age-related problems such as libido, osteoporosis, fatigue, and overall well-being. It's called "off-label use," and it's legal.

There's a growing number of men seeking treatment with testosterone therapy to counter the effects of aging, but there is little evidence to support this use, says the Institute of Medicine in a news release.

However, testosterone therapy has been linked with prostate cancer, so many doctors are wary of prescribing it. Older men are already at high risk for prostate cancer.

"We live in a society where people are looking for an anti-aging drug, and testosterone is a very popular candidate. ... Testosterone levels do go down as men age," Blazer said. "We're saying, let's get the answers rather than prescribing this drug as a panacea for many of the problems of the aging process."

Eli Chester Ridgway, MD, president of The Endocrine Society and chief of endocrinology at the University of Colorado Health Sciences Center, offered his opinion of the report.

"It's time to cut through the feelings and hopes out there that aging symptoms can be cured by testosterone," Ridgway tells WebMD. "Any practicing endocrinologist wants to know if there truly is a benefit to giving testosterone."


Dramatic Surge in Gel, Patch Prescriptions

An estimated 2 million prescriptions for testosterone therapy were written in 2002 for thousands and thousands of men -- a dramatic increase since the patch and gel were developed, Blazer said. Most were prescribed for middle-aged men.

His committee listened to prominent researchers and reviewed the available scientific literature on testosterone therapy. They identified only 31 trials involving older men. Most studies were quite small with fewer than 50 participants, and only one lasted longer than a year.

"We quickly determined that more clinical trials are needed ... and that the most immediate goal should be to establish whether testosterone therapy results in clear benefit for aging men," Blazer said.

The committee's recommendations:

  • Small, short-term studies looking at immediate risks and benefits should be conducted -- whether strength, sexual function, mental function, and general well-being are improved. If those studies do not show benefits, "then a long-term study would not be warranted," Blazer said.
  • The studies should involve only men age 65 and older, since that age group has the lowest testosterone levels and would therefore shed light on the benefits of this therapy, if any.
  • Men with high risk of prostate cancer should be excluded from studies.
  • Studies should also assess increased risk of prostate cancer.

Testosterone therapy should not be viewed as a preventive measure for age-related conditions, Blazer said. "To date, the evidence is almost nil -- virtually nonexistent.

"Until the efficacy and safety of testosterone therapy in older men is firmly established, we believe that its use is appropriate only for those conditions approved by the FDA and that it is inappropriate for wide-scale use to prevent possible future disease or to enhance strength or mood in otherwise healthy older men," Blazer said.

The committee said they found no evidence of major adverse effects from testosterone therapy, but they add that the evidence for its safety is lacking.

"There are alternative treatments for many of these [age-related] problems, some on the market, some being developed ... that may have lower risk than testosterone therapy," he said.

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SOURCES: Institute of Medicine. Dan Blazer, MD, professor of psychiatry and behavioral sciences, Duke University Medical Center. Eli Chester Ridgway, MD, president, The Endocrine Society; chief of endocrinology, University of Colorado Health Sciences Center.
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